Telephone receiver



July 28, 1925.

c. R. MOORE TELEPHONE RECEIVER Filed Jan. 19, 1923 WI 9 9 i 1W 4/ V i. k a A 6 /nve/7/0r- Char/es R Moore.

Patented July 28, 1925.

' UNITED STATES 1-,541,172 PATENT OFFICE.

CHARLES R. MooRE, E MAPLEWOOD, NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, on NEW YORK, N, Y., A ooRPoRA'rIoN OF NEW YORK.

TELEPHONE RECEIVER.

Application filed January 19, 1923. Serial No. 613,622.

which is capable of accurately and faithfully translating electrical impulses into sound vibrations.

In accordance with the features of this invention means are provided for sup-porting the armature of the magnetic system in a receiver so that a floating center of oscillation will be produced. Specifically the invention provides an armature which is yieldingly supported at substantially all points by a plurality of leaves of thin material, such as paper or foil, loosely disposed on each side thereof so as to provide air films between adjacent leaves and thereby form an air damping means, as Well as a supporting means, for controlling the resonance effects of the armature and the parts attached thereto and to insure substantially equal response at all frequencies for constant cur-.

rent input.

In the drawing: i i

Fig. l is a cross section through a receiver employing the invention:

Fig. 2 is an end view with the poles broken away to show the armature supporting means:

Fig. 3 shows a modification of the invention:

Fig. 4 shows another modification thereof.

ieferring to the drawings, the invention is shown as applied to a telephonic receiver similar to the type disclosed in Patent No. 1,365,898, issued June 18, 1921, to H. C. Egerton. The magnetic structure comprises a permanent magnet 6 tothe opposite ends of'which magnetic pole pieces 7 and 8 are respectively secured. Each pole piece is provided with a pair of pole-extensions 9-9 supported to receive the translating coil 10 therebetween which is wound on a hollow non-magnetic core 40. The pole piece 7 is secured tothe upper side of the magnet" thereof so as to bring the pole extension 9-9 of one pole piece opposite the pole extension 9.9 of the other pole piece. The coil. 10 is secured in place by the pole pieces and their extensions. The armature '13 is supported within the core of coil 10 by means of a plurality of thin leaves 41, of foil or paper, loosely and preferably equally disposed on each side. of the armature 13. A sufiicient number of layers should be provided to prevent the armature when vibrating from striking the pole extcnsions 99. For convenience in assembling, the leaves 41 may be loosely secured by their centers to the armature 13 by any suitable means such as a rivet 42. Longitudinal movement of the ar- .mature 13 is prevented by leaves 41 abutting against the pole extensions 9-9. The end 15 of the armature carries a rod 16 secured to the vibratory diaphragm 17.

Each of the pole extensions 99 are of the same polarity as the ends of the magnet 6, with which they are respectively associated and as the armature 13 depends on the passage of telephonic current through the coil 10 for magnetization the pole pieces 99 of ,opposing poles normally exercise a balancing attraction thereon. The passage of fluctuating voice currents through the coil 10 induces magnetic flux in the armature which changes in direction and strength in accordance with the voice currents, developing a corresponding variance in attraction and repulsing of the armature 13 relative to the pole extensions 9-9 to move the armature. tion to the diaphragm 17which translates this motion into sounds corresponding to the telephonic current traversing the coil 10.- An armature supporting means comprising the plurality of sheets of thin paper or foil is disposed on each side of the armature for both supporting it and controlling its vibrations. As these leaves bear against the armature uniformly at substantially all points the armature is not restricted to any definite center of oscillation but seeks its own center the position of. which depends upon the amplitude and frequency of the motion and the mass of the moving system and the load thereon. This arrangement provides a device which will more accurately translate sound vibrations than one in which the armature is restricted to oscillate about a fixed point. With the leaves The armature imparts mo loosely disposed as they must be for the purpose of proper operation, air films are formed between adjacent layers and an efficient air damping means is thereby provided, inasmuch as energy is dissipated by the inward and outward flow' of the air between the layers of f'oil pr paper when the armature vibrates. This damping effect controls the vibrations-at resonance. and insures substantially equal response at all frequencies to constant current input.

The magnetic structure and the diaphragm may be mounted in any suitable manner and are shown as supported in a face plate 30, preferably of non-magnetic material, having a recess 31 in the rear thereof to receive the diaphragm 17 which is retained therein between annular members 32-;32, preferably of yielding material. A metal retaining ring 33 preferably of nonmagnetic material, is-secured to the rear surface of the front plate to hold the diaphragm in place. The magnetic structure is secured to the front plate by means of screws 34, 35 and 36. The front plate 30 has an extension 51 with a small opening 52 therethrough, the extension being designed to support a suitable-horn, not shown. In practice a housing, not shown, is usually provided for covering the magnetic structure and is supported in any suitable manner on'the rear of'pla'te 30.

In the modification as shown in Figs. 3 and 4, the leaves are not assembled with the armature 13. Pins 50-50 are therefore provided to prevent any longitudinal movement.

In Fig. 4 the armature supporting means is formed by wrapping a sheet of foil or paper loosely around the armature.

- The invention claimed is:

1. In a sound reproducing instrument, a

- magnetic system, an armature therefor, and

means for supporting said armature for free vibration under control of sald magnet system, comprising leaves of thin material to poles of sai magnet, an armature associated provide a floating center of oscillation therefor. 4

2. A telephone receiver comprising a. permanent ma net, a translating coil at the with said coil, and means comprising a plurality of layers of thin material extending for a substantial distance each side of the poles, a stifi center of oscillation of said armature for supporting said armature said layers being loosely disposed withrespect to each other to form. air films therebetween;

. 3. A telephone receiver comprising a permanent ma'gnet','a translation coil having a hollow core associated with said magnet, an armature extending through said coil and means within said coil supporting saidplurality of-layers of thin material loosely disposed on each side of said armature.

6. A telephone receiver comprising a permanent magnet, a bifurcated pole extension on each end thereof, a translating coil supported between said pole extensions, an armature extendlng through said coil in operative relation to said extension, a diaphragm associated with said armature,

means for yieldingly supporting said armature within said coil, comprising a plurality of layers of thin material loosely disposed on each side of said armature, and means for transmitting vibrations between said armature and said diaphragm.

7. In a sound reproducing instrumentfa polarizing magnetic system having spaced armature extending between said poles and adapted to vibrate as a unit in accordance with magnetic variations rep- .resenting sounds, and means consisting wholly of stacked sheets of thin, flexible, light material extending throughout the said poles, for supporting said armature and damping its vibrations.

In witness whereof, I hereunto subscribe my name this 16 day of January A. D., 1923.

CHARLES R. MOORE.

within said coil, said meanscomprising a length of said armature included between 

